Third-party installer packages may not be installable by the macOS 10.12.4 OS installer

With the release of macOS 10.12.4, it appears that Apple has made a change to the OS installer that blocks the installation of third-party packages which have been added to the OS installer. In my testing, I’ve verified the following tools are affected:

In each case, the OS install process proceeds without issues until the OS installer tries to install the third party installer package. At that point, the installation process fails and displays the message shown below:

The package "Package Name Goes Here" is not signed.
Quit the installer to restart your computer and try again.

5. Change no other options from their default settings.
6. Build the NetInstall set.

Once the NetInstall set is built, boot a Mac or VM from the NetInstall set and run the OS installation process. In my testing, the OS install process has consistently failed when trying to install the unsigned third-party installer package. To show what this behavior looks like, please see the video below:

Note:The video has been edited to artificially reduce the amount of time the OS installation process takes to run. Run time of the pre-edited video was 21 minutes 18 seconds.

To replicate the successful install behavior, use the process shown below:

Pre-requisites

A Mac upgraded to macOS 10.12.4

System Image Utility

A macOS 10.12.4 installer

A third-party installer package which has been signed with a Developer ID Installer certificate.

4. Select option to add an additional installer and add the signed third-party installer package.

5. Change no other options from their defaults.
6. Build NetInstall set

Once the NetInstall set is built, boot a Mac or VM from the NetInstall set and run the OS installation process. This time, the installation process of the third party installer package should succeed. To show what this behavior looks like, please see the video below:

Note:The video has been edited to artificially reduce the amount of time the OS installation process takes to run. Run time of the pre-edited video was 20 minutes 9 seconds.

Workarounds

Since the new behavior is specific to the 10.12.4 installer, my recommendation at this point is to use the macOS 10.12.3 installer where needed. Once the OS is installed, update to later versions of macOS Sierra as a post-installation task.

I have been using this method. NetRestore is kind of nice too, essentially does what autodmg does. If you bless the nbi folder and put it on USB, add in a partition disk and auto install step, you can get a USB installer that you boot from and push no buttons to get a system restored in under 10 minutes typically. Maybe I can send some screen shots to you Rich and you could add that bit if you are interested. ping me nessts on slack if you want to discuss this more, because i know i can be confusing at times.

Is this still an issue on High Sierra (10.13.4)? I have a System Image Utility NetInstall creation that is failing with ‘error 2’ and when reviewing the System Image Utility log, the error seems to come from the CreateConfigurationProfilesInstallerPkg phase…